Boiler plug



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May 22, 1923.

Registered May 22, 1923.

UNITED STATES FREDERICK E. KEY, OF ST. LOUIS, MISSOURI.

BOILER PLUG.

Application led March 21, 1918. Serial No. 223,858.

To all whom it may concern:

Be it known that I, FREDERICK E. KEY, a citizen of the United States ofAmerlca, a resident of the city of St. Louis, State of Missouri,` haveinvented certam new and useful Improvements in Boiler Plugs, of whichthe following is al full, clear, and exact description, reference beinghad to the accompanying drawings, forming a part of this specification.

My invention relates t0 improvements 1n boiler plugs, one of the objectsbeing to p roduce a strong and simple plug for closing openings in steamboilers and the like.

Another object is to produce a highly efiicient leak-proof plugincluding a ilexible packing member, and having its elements soconstructed and arranged that the packing will be firmly forced onto itsseat by the fluid pressure in the boiler, instead of by a screw or thelike.

A further object is to provide a plug of this kind' adapted lto beeasily and quickly applied to and removed from a boiler. Another objectis to furnish a plug capable of being applied and removed an indefimtenumber of times without materially impairing the efficiency of itspacking.

An important object is to provide an efiicient boiler plug that can beeasily applied and secured from the exterior of the boiler. Under someconditions, for example, in making tests required of some types of waterlegs, all of the elements of the plugs must be inserted through theopenings to be closed thereby, and such plugs must withstand a very highdegree of hydrostatic pressure. .When so used, the plugs are onlytemporary closures for the openings. -They are removed when the test iscompleted. Ac tual tests have clearly shown that the new plug, appliedentirely from the outside of the boiler, will withstand a pressure muchgreater than 70() pounds per square inch. A very tight joint is producedby the fluid pressure forcing the packing onto its seat, and suchpressure does not mutilate or otherwise materially injure the packing.

Specifically stated, an object of the invention is to produce a singledevice consisting of al combination of elements from which all of theforegoing advantages are obtained.

Fig. I is a vertical section of a portion of the water leg of a boiler,showing two of my plugs properly applied thereto, and also illustratingthe manner in which the plugs can be applied and anchored from theexterior of the boiler.

Fig. II is an enlarged vertical section illustrating the details of aplug constructed in accordance with my invention.

Fig. III is an inside view of the plug shown in Fig. II.

vThe water leg shown in Fig. I is provided with walls 1, each havingplug-receiving openings To illustrate a preferred form of the invention,I have shown a plug consisting of an inside anchor A, a tension member Bsecured `to and extending outwardly from said insideanchor, and aclosure consisting of a packing holder C and packing D secured thereto.The inside anchor A is in the form of a bridge, longer than the diameterof the opening to be closed, but narrow enough (Fig. III) to passthrough said opening. When the plug is applied, as shown in Fig. II, theends of this bridge A are seated against the innerface ofthe wall 1.

The tension' member B is preferably in the form of a screw having a head4 which engages the outer face of the packing holder C, and also havinga threaded portion fitted to corresponding threads in the bridge orinside anchor A. By connecting the parts in this manner, I enable theinside and outside elements to be adjusted toward and away from eachother. The inside anchor A can be adjusted away from the. packing andpacking holder, as shown at the upper portion of Fig. I, and while theparts occupy these relative positions...the inside anchor can be veryeasily and quickly inserted through the opening in the water leg of theboiler. The manner of' inserting the inside anchor is suggested by theposition of the plug at the upper portion of Fig. I.

After the ends of the inside anchor A have been sea-ted on the innerfare of the wall 1, the screw B can be easily rotated from the exteriorof the boiler so as to advance the packing holder toward the anchor. Forrea.- sons which will be hereinafter pointed out, it is not necessary touse a wrench or other tool in tightening the plug. The screw head 4 canbe turned by hand until the packing holder C engages the outer face ofthe wall 1, and the packing will be tightened automatically by theoutward pressure of the fluid in the boiler.

The closure includes the packing holder` C in the form of a cup havingan annular flange 5 turned toward the inside anchor A and adapted t0seat against the outer face of the wall l. The internal diameter of theannular flange 5 conforms approximately to the diameter of the openingto be closed, so there is no abrupt offset or shoulder between the wallof the opening and the inner face of said annular flange. The packing Dis preferably made of flexible material, such, for example, as leatheror rubber. It conforms approximately to the shape of the cup-shapedpacking holder C, and it is seated on the inner face of said holder. Thepacking may be secured to the holderr by means of a clamping disk 6surrounding the screw B and contacting with the inner margin of thepacking; and a clamping nut mounted on the screu7 so as to retain thedisk 6 in firm engagement with the packing.

It is important to note that the packing has a free, flexible,expansible annular flange 8 which extends from the annular flange 5 toengage the circular wall of the opening 3. This free exible, expansibleannular flange is exposed directly to the outward pressure of the fluidin the boiler, so that the fluid pressure will force said free flangeinto firm engagement with its annular seats, and at the same time placethe screw B under tension. The packing is thus automatically forced intofirm engagement with its seats, a very tight joint being obtained by thepressure of the fluid on the packing, instead of by tightening the screwB.

Since the inside diameter of the annular flange 5 conforms approximatelyto the internal diameter of the plug-receiving opening, there is noabrupt corner to cut or otherwise mutilate the packing when the latteris firmly seated by the fluid pressure. The'elements of the plug are soconstructed and arranged that the flexible packing is merely placedunder compression and forced onto smooth seats to form a seal betweenthe annular flange 5 and the outer face of the wall 1. The plug cantherefore be applied and removed an indefinite number of times withoutmaterially impairing the efficiency of the packing. A l Although made offlexible material, the

'- packing is backed, or reinforced, by the lanchor A. The plug is thusfirmly secured to the boiler, but it can be easily removed by merelyturning the screw B and thereafter withdrawing the anchor, as suggestedby the upper portion of Fig. I.

1. A boiler plug comprising an inside anchor adapted to engage the innerface of the boiler wall to which the plug is applied, a tension membersecured to and extending outwardly from said inside anchor, and aclosure comprising a packing holder secured to said tension member andadapted to en-.

gage the Outer face of the boiler wall, and afreely yieldable packingring having an annular outer marginal portion secured'to said packingholder and a free, flexible annular inner marginal portion conforming toand adapted to be seated against the wall of the opening to beV closed,said packing ring being exposed to receive the outward pressure of thefluid, so that the fluid pressure will force said annular marginalportions into engagement with their seats and at the same time place theanchored tension member underf tension'.

2. A boiler plug comprising an inside anchor adapted to engage the innerface of the boiler wall to which the plug is applied,

said inside anchor consisting of a bridgeY longer than the diameter ofthe opening to be closed but small enough toy be wholly inserted throughsaid opening, a tension member secured to and extending outwardly fromsaid inside anchor, and a closure secured by said inside anchor, saidclosure including a packing holder in the form of a cup having anannular flange turned toward said inside anchor, and adapted to engagethe outer face of the boiler wall, the internal diameter of said annularflange conforming approximately to the diameter of said opening, and a'packing ring arranged within said cup and provided with a free, flexibleannular packing flange engaging the inner` face of the first mentionedflange and the wall of said opening, said packing ring also having anannular packing flange engaging the inside face 0f said cup, saidannular packing flanges being exposed to receive the outward pressure ofthe fluid, so that the fluid pressure will force said annular packingflanges into engagement with their annular seats and at the sametime'place the anchored tension member under tension.

In testimony that I claim the foregoing I hereuntov affix mysignature.

FREDERICK E. KEY.

